1. Field of the Invention
The present invention relates, in general terms, to clutches of the kind conventionally used for equipping motor vehicles.
2. Summary of the Prior Art
As is known, such a clutch substantially comprises, transversely, a first plate, commonly called a reaction plate or flywheel, intended to be fixed in rotation to a first shaft, in practice a drive shaft such as the output shaft of the engine in the case of a motor vehicle, a friction disk intended to be fixed in rotation to a second shaft, in practice a driven shaft such as the input shaft of a gearbox in the case of a motor vehicle, a second plate, commonly called a pressure plate, fixed in rotation to the reaction plate whilst being movable axially in relation to the latter, a component, called a cover, fixed in rotation to the reaction plate and coupled to the latter in the axial direction, and elastic means which, bearing on the cover, are designed to continuously stress the pressure plate towards the reaction plate so as to clamp the friction disk axially between said plates.
The reaction plate may be a generally flat component, in which case, in order to define the volume required to accomodate the friction disk and its movement, the pressure plate and the elastic clamping means associated with the latter, the cover is itself generally bell-shaped.
Alternatively, the opposite arrangement may be adopted, the reaction plate itself having on its inner periphery an axial rim adapted to define said volume, in which case the cover is generally flat.
As is also known, a clutch is usually equipped with a toothed starter ring.
More often than not, this toothed ring is carried directly by the reaction plate, either being integral with the latter or consisting of a component separate from said reaction plate, and formed for example by appropriately rolling to a circular configuration an initially straight bar, which is then appropriately attached to the reaction plate.
In practice, the toothed starter ring is more often than not an integral part of the reaction plate only when, the latter being generally flat, it may be very readily formed on the edge of the reaction plate.
Its axial dimension is then necessarily limited.
A general objective of the present invention is to provide an arrangement whereby it may be given any required axial dimension, taking beneficial advantage of the arrangement in which, as described for example in U.S. patent application Ser. No. 489,531 filed Apr. 28, 1983, the reaction plate is an assembly formed by two separate parts appropriately fastened together, consisting of a supporting bracket, by means of which it may be fixed to the shaft in question, and a reaction element with which the friction disk can interact.